Orbital Pump Eccentric Deformable Element Sealing
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Solution Overview
Problem
Pumps used for delivering liquid additives like urea-water solutions for exhaust-gas purification face challenges such as freezing at low temperatures, which can damage components, and require high dosing accuracy while maintaining durability and reliability, especially in the context of the SCR method.
Innovation Solution
An orbital pump design featuring a rotatable eccentric and a deformable element between the pump housing and the eccentric forms a delivery duct, allowing for precise liquid delivery with minimal cross-influences and enhanced durability through radial clamping and sealing mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump is designed with intensive contact with liquid additive for effective delivery, then delivery efficiency is improved, but vulnerability to freezing damage increases
Solution Approach 1:
The pump incorporates a flexible membrane that separates the liquid additive chamber from the pumping mechanism. This membrane allows the pump to maintain intensive contact with the liquid for effective delivery while protecting the mechanical components from direct exposure to freezing temperatures and potential damage from volume expansion during freezing.
2Reliability
If the delivery module is evacuated upon deactivation to prevent freezing damage, then component durability is improved, but resumption of delivery becomes more difficult
Solution Approach 1:
The pump system dynamically adjusts its operational state based on temperature conditions. During normal operation, the pump maintains liquid contact for efficient delivery. When freezing temperatures are detected or anticipated, the system transitions to a protected state where the flexible membrane isolates the liquid from mechanical components, preventing freezing damage while allowing quick resumption of delivery when conditions improve.
3Reliability
If the pump components are designed to be flexible to withstand volume expansion from freezing, then freezing resistance is improved, but dosing accuracy deteriorates
Solution Approach 1:
The pump design segments the system into a flexible protective outer structure and a rigid precision dosing mechanism. The flexible membrane and housing accommodate volume expansion from freezing, while the rigid internal dosing components maintain precise positioning and dimensional stability, ensuring accurate liquid delivery measurements are not compromised by external flexibility.
4Measurement precision
If the pump uses an orbital design with eccentric and deformable element, then dosing accuracy is improved, but structural complexity increases
Solution Approach 1:
The orbital pump design merges the drive mechanism and pumping action into a single integrated eccentric-deformable element system. The rotating eccentric directly actuates the deformable element to create the pumping action, eliminating the need for separate drive trains, linkages, or actuation mechanisms. This integration achieves precise dosing control while minimizing the number of components and overall structural complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The pump achieves improved durability and dosing accuracy, reducing the risk of damage from freezing and ensuring reliable operation over long periods with precise liquid delivery, even under varying conditions.
Implementation Method 1
an eccentric which can be rotated relative to the pump housing about a geometric axis (53)... The deformable element (7) is pressed in sections by the eccentric (5) against the pump housing (2)
Data Source
AI summary
A pump for conveying liquid includes a pump housing having an inlet, an outlet, an inner circumferential surface and a geometric axis. An eccentric in the housing is rotatable about the geometric axis relative to the housing. A deformable element is disposed between the inner circumferential housing surface and the eccentric. A delivery duct from the inlet to the outlet is formed by the deformable element and the inner circumferential housing surface. The deformable element is pressed against the housing by the eccentric in sections so that a displaceable seal of the duct and a closed pump volume in the duct are formed and are displaceable to convey the liquid along the duct from the inlet to the outlet by rotation of the eccentric. A receptacle, accommodating an edge region of the deformable element, is formed by the inner circumferential housing surface and a counter bracket.